1 //: So far the recipes we define can't run each other. Let's fix that.
  2 
  3 :(scenario calling_recipe)
  4 def main [
  5   f
  6 ]
  7 def f [
  8   3:num <- add 2, 2
  9 ]
 10 +mem: storing 4 in location 3
 11 
 12 :(scenario return_on_fallthrough)
 13 def main [
 14   f
 15   1:num <- copy 0
 16   2:num <- copy 0
 17   3:num <- copy 0
 18 ]
 19 def f [
 20   4:num <- copy 0
 21   5:num <- copy 0
 22 ]
 23 +run: f
 24 # running f
 25 +run: {4: "number"} <- copy {0: "literal"}
 26 +run: {5: "number"} <- copy {0: "literal"}
 27 # back out to main
 28 +run: {1: "number"} <- copy {0: "literal"}
 29 +run: {2: "number"} <- copy {0: "literal"}
 30 +run: {3: "number"} <- copy {0: "literal"}
 31 
 32 :(before "struct routine {")
 33 // Everytime a recipe runs another, we interrupt it and start running the new
 34 // recipe. When that finishes, we continue this one where we left off.
 35 // This requires maintaining a 'stack' of interrupted recipes or 'calls'.
 36 struct call {
 37   recipe_ordinal running_recipe;
 38   int running_step_index;
 39   // End call Fields
 40   call(recipe_ordinal r) {
 41   ¦ running_recipe = r;
 42   ¦ running_step_index = 0;
 43   ¦ // End call Constructor
 44   }
 45   ~call() {
 46   ¦ // End call Destructor
 47   }
 48 };
 49 typedef list<call> call_stack;
 50 
 51 :(replace{} "struct routine")
 52 struct routine {
 53   call_stack calls;
 54   // End routine Fields
 55   routine(recipe_ordinal r);
 56   bool completed() const;
 57   const vector<instruction>& steps() const;
 58 };
 59 :(code)
 60 routine::routine(recipe_ordinal r) {
 61   if (Trace_stream) {
 62   ¦ ++Trace_stream->callstack_depth;
 63   ¦ trace(9999, "trace") << "new routine; incrementing callstack depth to " << Trace_stream->callstack_depth << end();
 64   ¦ assert(Trace_stream->callstack_depth < 9000);  // 9998-101 plus cushion
 65   }
 66   calls.push_front(call(r));
 67   // End routine Constructor
 68 }
 69 
 70 :(code)
 71 call& current_call() {
 72   return Current_routine->calls.front();
 73 }
 74 
 75 //:: now update routine's helpers
 76 
 77 :(replace{} "int& current_step_index()")
 78 int& current_step_index() {
 79   assert(!Current_routine->calls.empty());
 80   return current_call().running_step_index;
 81 }
 82 :(replace{} "recipe_ordinal currently_running_recipe()")
 83 recipe_ordinal currently_running_recipe() {
 84   assert(!Current_routine->calls.empty());
 85   return current_call().running_recipe;
 86 }
 87 :(replace{} "const string& current_recipe_name()")
 88 const string& current_recipe_name() {
 89   assert(!Current_routine->calls.empty());
 90   return get(Recipe, current_call().running_recipe).name;
 91 }
 92 :(replace{} "const recipe& current_recipe()")
 93 const recipe& current_recipe() {
 94   assert(!Current_routine->calls.empty());
 95   return get(Recipe, current_call().running_recipe);
 96 }
 97 :(replace{} "const instruction& current_instruction()")
 98 const instruction& current_instruction() {
 99   assert(!Current_routine->calls.empty());
100   return to_instruction(current_call());
101 }
102 :(code)
103 const instruction& to_instruction(const call& call) {
104   return get(Recipe, call.running_recipe).steps.at(call.running_step_index);
105 }
106 
107 :(after "Defined Recipe Checks")
108 // not a primitive; check that it's present in the book of recipes
109 if (!contains_key(Recipe, inst.operation)) {
110   raise << maybe(get(Recipe, r).name) << "undefined operation in '" << to_original_string(inst) << "'\n" << end();
111   break;
112 }
113 :(replace{} "default:" following "End Primitive Recipe Implementations")
114 default: {
115   if (contains_key(Recipe, current_instruction().operation)) {  // error already raised in Checks above
116   ¦ // not a primitive; look up the book of recipes
117   ¦ if (Trace_stream) {
118   ¦ ¦ ++Trace_stream->callstack_depth;
119   ¦ ¦ trace(9999, "trace") << "incrementing callstack depth to " << Trace_stream->callstack_depth << end();
120   ¦ ¦ assert(Trace_stream->callstack_depth < 9000);  // 9998-101 plus cushion
121   ¦ }
122   ¦ const call& caller_frame = current_call();
123   ¦ Current_routine->calls.push_front(call(to_instruction(caller_frame).operation));
124   ¦ finish_call_housekeeping(to_instruction(caller_frame), ingredients);
125   ¦ // not done with caller
126   ¦ write_products = false;
127   ¦ fall_through_to_next_instruction = false;
128   ¦ // End Non-primitive Call(caller_frame)
129   }
130 }
131 :(code)
132 void finish_call_housekeeping(const instruction& call_instruction, const vector<vector<double> >& ingredients) {
133   // End Call Housekeeping
134 }
135 
136 :(scenario calling_undefined_recipe_fails)
137 % Hide_errors = true;
138 def main [
139   foo
140 ]
141 +error: main: undefined operation in 'foo'
142 
143 :(scenario calling_undefined_recipe_handles_missing_result)
144 % Hide_errors = true;
145 def main [
146   x:num <- foo
147 ]
148 +error: main: undefined operation in 'x:num <- foo'
149 
150 //:: finally, we need to fix the termination conditions for the run loop
151 
152 :(replace{} "bool routine::completed() const")
153 bool routine::completed() const {
154   return calls.empty();
155 }
156 
157 :(replace{} "const vector<instruction>& routine::steps() const")
158 const vector<instruction>& routine::steps() const {
159   assert(!calls.empty());
160   return get(Recipe, calls.front().running_recipe).steps;
161 }
162 
163 :(after "Running One Instruction")
164 // when we reach the end of one call, we may reach the end of the one below
165 // it, and the one below that, and so on
166 while (current_step_index() >= SIZE(Current_routine->steps())) {
167   // Falling Through End Of Recipe
168   if (Trace_stream) {
169   ¦ trace(9999, "trace") << "fall-through: exiting " << current_recipe_name() << "; decrementing callstack depth from " << Trace_stream->callstack_depth << end();
170   ¦ --Trace_stream->callstack_depth;
171   ¦ assert(Trace_stream->callstack_depth >= 0);
172   }
173   Current_routine->calls.pop_front();
174   if (Current_routine->calls.empty()) goto stop_running_current_routine;
175   // Complete Call Fallthrough
176   // todo: fail if no products returned
177   ++current_step_index();
178 }